1. Field of the Invention
The present invention relates generally to prosthetic devices for supporting or maintaining the position of mammalian tissue, and more particularly relates prosthetic support devices for breast tissue or breast implants.
2. Description of the Prior Art
Breast implants are conventionally and commonly used in a plurality of cosmetic and reconstructive surgeries. One of the most prevalent complications arising in the post-operative stage of the surgery is the displacement of the implant. Implants are prone primarily to three different malpositions: inferior, lateral and symmastia. When an implant is displaced inferiorly, also referred to as “bottoming out”, the distance from the nipple to the inframammary fold is increased. Lateral displacement results in the implant falling into the axilla. In the case of symmastia, the implant moves medially on the chest wall. The displacement of breast implants may be attributed to several factors including: surgical error, the gravity of the implant or the general weakness of the supporting tissue. Surgical error often results from the over-dissection of muscle and tissue while creating the pocket for the implant, which is thus inappropriately oversized.
The commonly accepted method for correcting malpositioned implants is capsulorrhaphy. Capsulorrhaphy relies on the capsule or scar tissue to repair and support a repositioned implant. As with many surgical correction procedures, capsulorrhaphy has inherent disadvantages and problems. The procedure generally requires a significant amount of time which can place undue stress upon a patient. For example, very often it can take 1.5 to several hours to repair one malpositioned implant due to the tedious process of making numerous suture bites with the capsules to close part of an improperly sized pocket due to dissection or other causes. Implant displacement can also be recurrent because the natural tissue and/or thin capsules of the patient's body may be or become too weak to support the breast implant using capsulorrhaphy. Several conventional methods and apparatuses have been developed to support implants and breast tissue.
Surgical meshes are an example of a device used for supporting, repairing or reinforcing tissue, or supporting and/or maintaining the position of natural anatomical structures (e.g. the heart or breast tissue), or certain anatomical replacement structures (e.g. breast implants). More specifically, surgeons have used two-dimensional porous sheets or surgical meshes for supporting breast implants or supporting natural breast tissue. An example of such is disclosed in U.S. Patent Application Publication No. US2006/0030939 by applicant Robert E. Frank. The Frank published patent application discloses an implantable prosthesis for positioning and supporting a breast implant. The prosthesis is formed from a flat mesh which is cut to a desired geometry or dimensions, and the edges are then sewn or sutured together to form a sling-shaped receiving area for receiving the breast implant. As shown in FIGS. 7 and 8 and in paragraph [0034] and [0035] of the Frank published patent application, the first portion 14 and the second portion 16 are formed from a sheet 12 of a prosthetic material, with the first and second portions 14, 16 separated by a fold line 18. The side walls 24, 26 of the first portion 14 and the side walls 30, 32 of the second portion 16 are fixed together by sutures, a suitable adhesive or tacking to maintain the shape of the implantable prosthesis.
There are several disadvantages with the prosthesis disclosed in US2006/0030939. For one, shaping and folding a two-dimensional sheet or mesh to form a three-dimensional prosthesis is cumbersome, and it is also often difficult to obtain the desired three-dimensional shape. Also, cutting and trimming a mesh product to fit the size or contour of a breast implant in an operating room may add additional technical difficulties, prolong the surgeon's operation time and create fine, albeit sterile, dust, which is a byproduct that is undesirable to have in a clean operating room. Furthermore, sewing or suturing folded mesh edges together may result in the formation of stiff seams, which may generate palpability problems or may interfere with the detection of breast cancer tumors. Additionally, the existence of mesh folds, wrinkles or seams in the sewn together prosthesis or support may increase the chance of hosting bacteria and the risk of infection at the surgical site. In addition, the mesh prosthesis or support may collapse under its own weight after it is sewn into its desired form, causing the handling of the mesh to be more cumbersome than it would be if the mesh could maintain its shape naturally.
U.S. Pat. No. 6,951,534, which issued to Michael J. Girard et al., discloses an elastic cardiac support device which is constructed from a biocompatible mesh material. The device is stated to be highly compliant, and can fit to and comply with the shape of the heart when the heart is positioned within the device. However, if there is no anatomical structure within the support device, the device cannot hold its shape because of a lack of rigidity or stiffness.